/*
20241210
- based on tweetnacl 20140427 (http://tweetnacl.cr.yp.to/software.html)
*/
#include "crypto_hash_sha512.h"

#include "haslib25519.h"
#ifndef HASLIB25519

#include "crypto_uint64.h"

#define R(x, c) (((x) >> (c)) ^ ((x) << (64 - (c))))
#define Ch(x, y, z) (((x) & (y)) ^ (~(x) & (z)))
#define Maj(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
#define Sigma0(x) (R((x), 28) ^ R((x), 34) ^ R((x), 39))
#define Sigma1(x) (R((x), 14) ^ R((x), 18) ^ R((x), 41))
#define sigma0(x) (R((x), 1) ^ R((x), 8) ^ ((x) >> 7))
#define sigma1(x) (R((x), 19) ^ R((x), 61) ^ ((x) >> 6))

static const crypto_uint64 K[80] = {
    0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL,
    0xe9b5dba58189dbbcULL, 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
    0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL, 0xd807aa98a3030242ULL,
    0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
    0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL,
    0xc19bf174cf692694ULL, 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
    0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL, 0x2de92c6f592b0275ULL,
    0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
    0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL,
    0xbf597fc7beef0ee4ULL, 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
    0x06ca6351e003826fULL, 0x142929670a0e6e70ULL, 0x27b70a8546d22ffcULL,
    0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
    0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL,
    0x92722c851482353bULL, 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
    0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL, 0xd192e819d6ef5218ULL,
    0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
    0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL,
    0x34b0bcb5e19b48a8ULL, 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
    0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL, 0x748f82ee5defb2fcULL,
    0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
    0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL,
    0xc67178f2e372532bULL, 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
    0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL, 0x06f067aa72176fbaULL,
    0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
    0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL,
    0x431d67c49c100d4cULL, 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
    0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL};

static void blocks(crypto_uint64 *z, const unsigned char *m, crypto_uint64 n) {

    crypto_uint64 b[8], a[8], w[80], t;
    long long i, j;

    for (i = 0; i < 8; ++i) a[i] = z[i];

    while (n >= 128) {
        for (i = 0; i < 16; ++i) w[i] = crypto_uint64_load_bigendian(m + 8 * i);
        for (i = 16; i < 80; ++i)
            w[i] =
                (sigma1(w[i - 2]) + w[i - 7] + sigma0(w[i - 15]) + w[i - 16]);

        for (i = 0; i < 80; ++i) {
            for (j = 0; j < 8; ++j) b[j] = a[j];
            t = a[7] + Sigma1(a[4]) + Ch(a[4], a[5], a[6]) + K[i] + w[i];
            b[7] = t + Sigma0(a[0]) + Maj(a[0], a[1], a[2]);
            b[3] += t;
            for (j = 0; j < 8; ++j) a[(j + 1) % 8] = b[j];
        }

        for (i = 0; i < 8; ++i) {
            a[i] += z[i];
            z[i] = a[i];
        }

        m += 128;
        n -= 128;
    }
}

int crypto_hash_sha512_tinyssh(unsigned char *o, const unsigned char *m,
                               unsigned long long n) {

    unsigned long long i;
    unsigned char x[256];
    crypto_uint64 b = n;
    crypto_uint64 h[8] = {0x6a09e667f3bcc908ULL, 0xbb67ae8584caa73bULL,
                          0x3c6ef372fe94f82bULL, 0xa54ff53a5f1d36f1ULL,
                          0x510e527fade682d1ULL, 0x9b05688c2b3e6c1fULL,
                          0x1f83d9abfb41bd6bULL, 0x5be0cd19137e2179ULL};

    blocks(h, m, n);
    m += n;
    n &= 127;
    m -= n;

    for (i = 0; i < sizeof x; ++i) x[i] = 0;
    for (i = 0; i < n; ++i) x[i] = m[i];
    x[n] = 128;

    n = 256 - 128 * (n < 112);
    x[n - 9] = b >> 61;
    crypto_uint64_store_bigendian(x + n - 8, b << 3);
    blocks(h, x, n);

    for (i = 0; i < 8; ++i) crypto_uint64_store_bigendian(o + 8 * i, h[i]);
    return 0;
}

#endif
